Movement and circulation of water vapor is typically accomplished using a blower in which the motor and bearings for the blower are isolated from the water vapor through the use of various seal arrangements within the blower housing. Isolating the internal components of the blower from the water vapor prevents corrosion of the components. This isolation further protects the motor to prevent undesired electrical issues during operation of the blower.
Prior art blowers designed for moving water vapor commonly use brushless permanent magnet motors. Such motors can be sealed from the water vapor moving through the blower quite easily, but sealing around rotating parts of the blower requires a more complex design than typical blowers. For example, the rotating parts of a blower often require lubrication for efficient operation and for cooling to prevent damage from over-heating. Leakage from the lubricant or coolant for the blower's rotating parts may cause contamination of the water vapor, or vice versa. Since seals often permit some amount of leakage, contamination of the water vapor with lubricant or coolant is disadvantageous for the operation of typical water vapor blowers. Complex designs are thus necessary to minimize and manage leakage and contamination issues within the blower, which is also a disadvantage in providing an effective blower design.
In addition to the disadvantages presented by the issues of leakage and contamination within the blower, the isolation of the motor and other internal blower parts from the water vapor makes it difficult to adequately contain the heat that is generated by these parts during operation of the blower. This heat is lost to the environment, which affects the efficiency of the system. To contain the heat using prior art blower designs, an additional system is needed to collect and manage the heat, which adds to the complexity, size and cost of the system.
In view of the foregoing, there is a need for a blower for moving and circulating water vapor, and preferably sub-atmospheric water vapor, that can operate efficiently without leakage or contamination that affects the water vapor moving therethrough, and that can prevent heat loss from the system, all without suffering from the drawbacks common to prior art blower designs that tend to affect performance, operation and efficiency. Accordingly, it is a general object of the present invention to provide a blower for moving and circulating water vapor that removes the problems of leakage and heat loss, particularly by immersing the entire blower in the water vapor. Gas foil bearings used in the present invention are lubricated by the water vapor itself, as opposed to a separate lubricant, so there is no possibility of the above-mentioned contamination typically associated with prior art blowers and the drawbacks associated therewith. Further, the heat generated by the blower is transferred to the water vapor, and the heat can then be recovered through common heat exchanger methods since water vapor is highly effective at carrying and transferring thermal energy.